***Water-based stains often dry too fast for even wipe-off, especially on large surfaces.

Solvents can be added to slow the drying, but these aren't widely available or understood, and adding a solvent changes the intensity of the color, requiring another adjustment. Finishers have to adjust their coloring procedures to take into account the fast drying of water-based stains.

***Spray gun clean up with water-based finishes is much more critical and difficult than with lacquers (but not more critical than with conversion varnish).

Lacquer can simply be rinsed out by running thinner through the gun and hose, if there is one. But spray guns often have to be disassembled and cleaned when water-based finishes are used. Running warm water, or even a solvent thinner, through the gun is not the sure cleaning procedure it's often made out to be. Finishers have to adjust their gun-care procedures.

This is not a complete list of adjustments that have to be made. For example, it doesn't include the critical minor adjustments in gun speed and distance necessary when spraying any new finish to get an orange peel-free surface. Clearly, finishers are faced with a considerable task when switching to water-based finishes. It's no wonder there is resistance.

The situation is further complicated by the objection of many to the appearance of water-based finishes on some woods and the absence of a cost-benefit incentive such as that associated with HVLP. In fact, contrary to the claims of many suppliers, there is usually a significant cost increase, even factoring in the higher solids of water-based finishes and possible reduced insurance costs.

Manufacturers' roleI believe some of the resistance to switching to water base is caused by manufacturers, who over-hype their products, especially the small companies that sell only water-based products. The over-hyping is not as common among companies that sell a variety of solvent and water products; these companies don't care as much which product you buy, as long as you buy it from them.

The most obvious cases of over-hyping are the continued claims some companies make of improvements â€” often referred to as "generational" changes â€” that now make their water-based finishes equivalent to solvent-based when, in fact, the changes are just at the margins.

Over the last decade, finish companies working together with raw-materials suppliers have made noticeable improvements in durability, leveling, adhesion and reduced bubbling. But all of the problems listed above still exist, and finishers have to adjust to them. There is a limit to what can be done to make a finish not act like water when, by its very nature, it does contain a lot of water.

There was also hype surrounding turbine HVLP when it was introduced, but it tended to be more industry-wide rather than supplier-specific. For example, there was an often-repeated claim that the hot air produced by turbine HVLP spray guns reduces or even eliminates blushing in lacquer. This isn't true, because the air doesn't contact the finish until it has already left the spray gun. The atomization causes the finish to cool much more rapidly than the warm air can heat it.

In contrast, consider the claims of some water-based suppliers that their finish "burns-in" to the coat below, making the product equivalent to lacquer. Well, as mentioned above, the burn-in isn't equivalent. But this isn't the issue. Even if the burn-in were equivalent, the finish still isn't lacquer. There are many other significant differences, including the propensity to run on vertical surfaces, grain raising, drying time and ease of repair, that separate the two finishes and are ignored in these claims.